Oxidation cyclischer α-Aminoketone / Oxidation of Cyclic α-Aminoketones

Abstract

The 1,2,3,4-tetrahydro-isoquinolin-4-one 4 reacts as an α-amino ketone with periodate to give various products, the major compound being 1-hydroxy-1,2-dihydro-3,4-isoquinolinedione 12. Upon stepwise oxidation with Hg(II)-EDTA the 4-hydroxyisoquinolinium ion 14 is detected as an intermediate and its further oxidation with periodate gives rise to an almost identical product spectrum. Because 12 represents a carbinolamide with an additional 4-carbonyl group, this type was examined first. Acid catalysis was used because the reactive species mostly are iminium ions. With cyclic 1,3-dicarbonyl compounds, 1-substituted derivatives 17a, b are formed. With linear species 1-substitution is also observed, but the tautomeric forms 19a -c are obtained. The stable enones 24a, b result from alkyl ketones by ready autoxidation of the primary products. Base catalysis induces a ring contraction of 12 to the hydroxycarboxylic acid 25. Reaction of 12 with aniline and phenylhydrazine yields the easily oxidizable 1-substitution products 28 and 31.

Synthesis and Reactivity of Ortho-Palladated Phenylacetamides. Intramolecular C−N vs C−O Reductive Coupling after CO or XyNC Insertion into the Pd−C Bond. Synthesis of Isoquinoline- and Isocoumarin-Based Heterocycles

“…As observed for the previous C−N couplings, the decomposition is much faster for the unsubstituted derivative 1a (30 min at room temperature) than for its methyl-substituted analogue 1b , the latter requiring harsher reaction conditions (3 h at 61 °C). Compounds 11 are new members of the small family of imino derivatives of isoquinoline-1,3(2 H ,4 H )-dione. , The reaction of 1c with 1 equiv of XyNC gave a mixture containing a new organometallic derivative, probably the expected insertion product, and unreacted starting material, which could not be separated. However, heating this mixture at 60 °C for 24 h led to its gradual decomposition to give colloidal Pd, (tmedaH)I, and an almost quantitative yield of the new iminoisocoumarin derivative 1-(2,6-dimethylphenylimino)-3-( N , N -dimethylamino)-1 H -2-benzopyran ( 12c ), resulting from a C−O coupling.…”